Haier DW-86L338J Service Manual page 30

high temperature stage system and low temperature stage system. Do not open the two systems at the same time
during maintenance, and always separate one system from another.
*The humidity in the maintenance workshop should not be too high. In case of cloudy and rainy days, it is
forbidden to open the system. All pipelines of the machine, of which the system has been opened, shall be welded
immediately.
*Because the freezer has strict requirements for water in the system, when the pipelines of the freezer are
open, the pipelines should be sealed with tape immediately to prevent air from entering the system, and the opened
pipelines are required to be welded within 20 minutes;
7.5.3 Vacuum pumping
1) Connect the vacuum pump connector with the common connector in the middle of the pressure gauge, as
shown in Figure 2
2) Turn on the vacuum pump for vacuum pumping, and the vacuum degree is required to be less or equal to 3 Pa.
For pumping time, please refer to the attached precautions. See Figure 3
3) When the vacuum degree is reached, stop high pressure vacuumization first, and weld and seal the high
temperature charging pipe quickly (because the refrigerant pressure is too high, the high pressure cannot be sealed
when the freezer is refrigerating), and continue to vacuumize at low pressure for one hour. See Figure 4
4) Close the pressure gauge valve after one hour of low pressure vacuumization. At this time, the freezer is
required to be kept in negative pressure for more than one hour to check whether the system of the freezer is in a
vacuum state while observing whether the pressure gauge rises again, if this is the case, re-vacuumize more than one
hour and keep the freezer in negative pressure state for more than one hour. Continue the vacuumization until the
pressure does not rise, and then fill refrigerant.
[Precautions]
*Vacuum pumps with capacity more than 4 L must vacuumize for 12 hours
Figure 1
7.5.4 Refrigerant filling
1) When filling refrigerant for high temperature stage system, the freezer should be in a stop state, and then
fill refrigerant R290 with the filling capacity specified in the attached table! (The filling sequence of refrigerants fo
rDW-86L100J is R600A, R1150, and R50)
[Precautions]
*In order to ensure that the refrigerants are filled in place at one time, the steel cylinder must be placed upside
down when filling above refrigerants, as shown in Figure 5
2) When filling refrigerant for low temperature stage system, the freezer should also be in a stop state, then fill
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Figure 2
Below 3 Pa
Figure 3
Figure 4
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